Device for cutting screw-threads.



W. MURGHEY. Y

DEVICE FOR CUTTING SCREW THREADS.

APPLICATION FILED AUGgv-Z, 1912.

Patented 0@f;.20,191'4.

3 SHEETS-SHEET 1` v4WITNESSES W. MURCHEY. 4DEVICE FOR CUTTING SCREWTHREADS.

Patented Oct. 20, 1914.

APPLICATION FILED AUG. 26, 1912. L 1262.;

3 SHEETS-SHEET 2.

T ab

INVENTOR.

.Mura/ze W l ATTOR Y.

W'. MURCHEY.

n G 26,1912. 1,1 14,629. Patented 001.20, 1914.

' a SHEETS-SHEET a.

UNITED srarnsrarnivr oriucii.

WILLIAM MURCHEY, OF DETROIT. MICHIGAN, ASSIGNOR T0 WALTER H. JENNINGSAND CORNELIUS K. CHAPIN, OF DETROIT, MICHIGAN.

DEVICE FOR CUTTING SCREW-THREADS.

Specification of Letters Patent.

Patented Oct. 20, 1914.

Application iled August 26, 1912. Serial No. 716,954. v

of Michigan, have invented certain new and useful Improvements inDevices for Cutting Screw-Threads, of which the following is aspecification.

This invention relates to devices for cut ting screw-threads exterioilyof the work, and more particularly to that class thereof especiallyadapted for threading pipes and the like, and it has for one of itsobjects the provision of an improved die-head adapted to cut a taperthread and to open the chasers gradually as they progress longitudinallyof the work.

The invention has further for its object the provision of means wherebythe chasers will beautomatically opened or entirelyre. leased from thework after a certain length of thread has been cut.

A further object of the invention. resides in the provision of meanswhereby the length of thread to be cut may be varied within reasonablelimits without inter fering with the gradual o enin'g movement of thechasers during tie cutting operation. l

The invention has also for its object the provision of a reameiwherebythe inside lof the pipe end to he externally threaded, may be rcaniedout, this ieainei` coiisitnting one of the elements whereby the entirechaserrelieving mechanism is controlled.

Further objects of the invention will hereinafter appear and beparticularly defined in the claims. v

The invention has been clearly illustrated in the accompanyiiigldrawings, iiigwliich similar characters denote similar-parts, and inwhich* Figure 1 is a front view of a die-head embodying my invention.Fig. 2 is a central longitudinal section. thereof, online 2, 2 ofFig. 1. Fig. represents a similar sect-ion of the head and its spindle,on line 3, 3 of F 1. the supports or bearings for the spindle being'omitted. Fig. i shows areal.1 view of one of the chaser-carriers orsliding blocks. Fig. 5 is a side view thereof. Fig.

6 illustrates a cross-section of the spindle, on line 6, 6 of Fig. 8.Fig. 7 shows a side view of the chaser-carrying end of the head. Fig. 8represents a section of the head, on

I threading line 8, 8 of Figs. and 3. Fig. 9 isa section on line 9, 9 ofFigs. 2 and 3. Fig. 10 is a perspective View of the reamer employed inmy device. Fig. 11 is a side view of the slide-pin, on an enlargedscale.

Briefly stated, my improved die-head is particularly adapted for use inconnection with Aa power-driven nip'ple andI pipe machine in which thehead-spin dle is rotatable but non-shiftable longitudinally. The headcarries a number of thread-cutting chasers which are normally closed-into cut a thread exteriorly on a pipe, 4this cutting operation beginningwith the smallest thread-diameter. As the work is gradually drawn inwardby the pitch of the /thread-cutters, the latter aie gradually opened toreduce the required standard pipe threa taper which is generally ac-vcepted as one-sixteenth of an inch per one inch thread-length. when the.,desired thread-length has been cut, the cha-sers will he automaticallythrown outward andclear of the work, and it then requireshandmanipulation to bring them together again into their closed-inposition. A reainer for theinside and the end-face of the pipe is alsooperative simultaneously witli the thread-cutting operation, and by itsmovement longitudinally with Ithe pipe, the Chaser-relieving mechanismis operated.

Referring now to the drawings, 10 denotes the head-carrying spindleupon. which the head 11 is iirmly secured by a key 12 also a set-screw13 (see Fig. 2). Mounted and guided for radial movement in tlie face ofthe head 11, are a series of Chasercarrying slides 14 which are providedwith abutment-niembers shown herein 'as pins"l lpagairist the innerfaces of which the chasers or thread-cutting tools 16 rest. The latteraie fittel in slots 17 and held against clisplaceinnitY by set-screws18. The rear ends of each piii 15 is provided with an eXt'e ision 1f)the under-side of which is ei'igaged by a blade-spring 20, the latterbeing secured to' the hub-piji-rtion of th, head l1, so that eachspring` tends to push its particular slide 14 radially outward to openhe diechasersl Means are provided for ,fig variably limiting orcontrolling this radiallyfoutward movement of all the carriers 14 simltaneous'ly, these means consisting siibstaiitially of wh at may eternied die-levers 21, engaging the `u per or outer faces of the severalpins 15 respectively, and each having an inclined face 21 which is incontact with the beveled face 22 of an annular regulating member or ring22. The hub of this ring is rotatable on, and in screwthreadedengagement with a sleeve '23 which is slidable longitudinally butnon-rotatably mounted on the hub of the head 11, as for instance by ascrew-pin-and-slot connection 24 (see Fig. 3), and which is providedwith pairs of ears 25 between which the die-levers 2l above referred toare pivoted.

From the foregoing it will be understood that, under normal conditions(when the sleeve 23 is stationary and in the position shown in Fig. 2),a manual rotation of the ring 22 will result in either forcing the freeends of the die-levers 21 toward the axis of the carrier, or it willwithdraw its beveled face 22 in a rearward direction and thus allow thesprings 20 to move all the carriers 14: outwardly; all in accordancewith the direction of such rotation. It is, therefore, evident that inthis manner the thread-diameter of the Chaser-cut may be varied withinthe limits of the incline and movement of the beveled face 22 of saidring. In Fig. 2 the position of the ring 22 is substantially at itsextreme right or rearward adjustment, so that therefore theChaser-slides areopen for the largest diameter of pipe to be threaded.If the pipe should be smaller, the ring need only be screwed fartheronto the sleeve toward the front of the head, when the chaser slideswill be correspondingly contracted, and consequently a smallerthread-diameter will be out. i

As above stated, the present device is also organized in such a mannerthat the chasers vwill be gradually moved radially outward to correspondwith the standard taper of the desired screw-thread, and in thisinstance I rely entirely upon the longitudinal movement of the pipe intothe head to perform this function in an automatic manner. Furthermorethe chasers are preferably formed with their cutting teeth correspondingto this taper, although a straight cutting face may be employed. Itbeing remembered that the pipe is gradually drawn into the head throughthe screw-cutting action of the chasers, it follows that if theChaser-slides were held fixed in their once adjusted positions, the pipethread would be tapered only at the front end and for a length equal tothe thickness of the chasers, while the rear portion of the thread, fromthe back-face of the chasers to the rear end of the pipe, would ofcourse be straight c ylindrical and equal to the smallest diameter ofthe chasers. Now, in order to avoid this objectionable feature, the chaers, or rather their carriers 14 are so organized that they will begradually moved outward and thus produce a tapered thread regardless ofhow thick or how thin the chasers may be. This outward movement beingsuch as to correspond to the standard taper generally adopted forpipe-threads.

By referring to Figs. 2 and 11, it'will be noted that the outer face 15of the pin 15 is thus inclined, so that when the sleeve 23 is,

in some way or other, moved rearwardly,l

the nose of each die level will slide along this inclined face 15 andtherefore permit the spring 20 to assist in moving the chaserslideoutward, radially, in addition to the tendency which the cutting actionof the chasers naturally has to perform this function. This, then, meansthat the chasers will cut a continuously tapering thread as long.

as the lever nose rides on the pin-face 15, and until it has reached thedrop-off point 15 which allows a sudden outward movement of the slide 14sufficiently to completely disengage the chasers from the work. Fromthis it can be very readily understood that the actual length of thepipe thread to be cut depends entirely upon the length of travel of thelever-nose to the drop-off point 15, and also that the number of cuttingteeth longitudinally axially of the chasers does not in the least haveany influence upon the length of the pipe thread. In fact, two or threetooth-convolutions will suliice to form a perfect pipe thread of alength equal to that of the incline or taperface 15'; but I prefer toprovide a greater number of such convolutions because, when theactually-cutting front teeth become worn, the chaser-slides may beadjusted by the ring 22 to bring the succeeding teeth into operation, itbeing understood that the collar 38 should be adjusted correspondinglyto maintain that same particular length of thread. Hence it is evidentthat the life" of the chasers, as such, is very materially lengthened.In connection with the outward movement of the chaser-slides, it mayalso be ,mentioned that, even with the teeth formed on a taper asdescribed, the last teeth will never cut the work to the same extent asthe first or. front teeth, for the reason that the taper of the chaserscorresponds exactly to the inclined face 15.

While different methods may be readily devised to move the sleeve 23rearward at the same ratio at which the pipe enters the head 11, Iprefer to let the pipe, itself, perform this work, and I accomplish thedesired result by a reamer whereby the inside of the pipe-end is reamedout smooth and its end face is machined or squared to produce finishedwork. The reamer is herein designa-ted by the numeral 30, and it has afiange 31 against which the end of theA pipe P (see Fig. 3) will bedrawn by the thread-cutting action of the chasers, it being understoodthat the reamer has at. that time finished its work on the pipe-end.

lil-14,6%

rear ends of the rods 36 are adapted to rest against the front *faceof acollar 38 which is free to rotate and slide longitudinally on thespindle 10, and is in screwthreaded engagement with the rear end of thenon-rotatable sleeve 23, so that, by rotating the collar 38, Athe`reamer may be variably positioned relatively tothe head 11 and itsChaser-slides 14, when the sleeve 23 is in its normal position shown.`When the machine is idle, o'r rather until the reamer `is .forcedbodily rearward, the latter is maintained in its forward position by aplunger 39 slidably mounted in the central bore 10 ofthe spindle I0, andalso in a bushing 40 whereby the outward movement of the plunger islimited, as against a' spring 41'interposed between saidplunger and anabutment-rod 42. In order to enable the operator to vary the resistanceof they spring 41, the spindle l() has a fixed collar 43 upon 'which asleeve 44 isadJustably mounted to serve as a rest for a bar 45 passingthrough a slot 46 in the spindle 10 and, in turn, serving as a stop orabutment for the rear end of the rod 42. In recapitulation, theoperation is brieiy as followsz-The parts et thedie-head being normallyin theposition shown, the pipe I) is rought into Contact with thechasers. As the headn rotates` the pipe will be gradually drawn toward.and into the head, bringing' the pipoend into engagement with therea'nler until the end-face will bring up against the realner iange andthereupon move the reai'ner bodily rearward against thespring 41 andmoving the collar 38 longitudinally 1n unison with the pipe,rearivardly. This movement of the collar`38 results in drawing thesleeve 23, with its ring 22 and the die-levers, rearward so that thechaser slides may then move gradually ol'ltward and form a perfectstandard-taper pipe-thread until the point 15 has been reached and thechasers become released. It the pipe should be slightly under-size, thering can be moved `forward to bring the front Chaser-teeth into theproper diameter, without interfering with the point of engagementbetween the die-levers-21 and the slide-pins 15. The length ofpipe-.thread may' be varied by either substituting pins ha ving longeror shorter iuclines for those' shown at l5', or by changing the relativepositions between the slide-collar 38 and the sleeve 23, or bysubstituting diierent-length push rods for those shown at 36, but thepreferred way or manner of producing the desired result-is illustratedin detail in F ig. 2. It being remembered that the chasercarriers orslides 14 .do not move longitudinally of the axis of the'lead, itfollows that the pins l5 will always remain in the same positionlongitudinally of this axis. This includes of course the inclined face15 and the drop-ofi' point 15. Now inasmuch as the length` of the threadis controlled by the distance which the levers 21 travel from theirstarting oint (see Fig. 2) to; the drop-oli' point, it Nollows that ifthis travel is .by'any means shortened or reduced, the length of thethread may be varied in accordance with such change. Therefore Iaccomplish. this result by moving the sleeve 23 longitudinally of theheadaxis so as to bring the working nose of each lever 21 to the properdistance from the drop-oit point 15" in such a'manner that thefrontfteeth of the chasers, when worn, may be entirely disregarded. Inorder to make this matter clear let us suppose that thep'rsition of thereamer shown in Fig. 2 is exactly right for the front teeth of thechasers to produce the required thread- 95 length. Then after theseworking teeth (say about one-quarter of an inch chaser threadlength) hasbeen worn to that `extent or perhaps removed and ground off entirely, it

is evident that compensation must be made 10u for this one-quarter of aninch lack of teeth,

when it is desired to cut the pipe threads as before.' Hence it becomesnecessary to change the position of the sleeve 23 relative to the headso that then the pipe enterin g the-reinto will not commence to movevthessleeve 23 rearward by pushing against the reamer 30, until theactive chaser teeth shall commence to operate on the outside of thepipe. `In order to do this, I have pro- 110 rided an adjusting screw 50in screw-threauled engagement with the rear portion ot the sleeve 23 andabutting against the rear face or' the hub l1. lVhenever anv amount oflinear' distance of Chaser teeth is ground 115 away, the vsleeve 23should be pulled rearward tor this same amount or distance by adjustingthe screw 50i. so that when then the pipe engages the roamer 30. thelatter will be simply pushed rearwardly against the action of the spring4] without however disturbingl the sleeve 23 or the adjustment collar38, the relative position remaining as before.

Any convenient means may be employed 12.*'. to bring the parts tononaal, the machines of this character being usually equipped with ahand operable lever L in engagement `with a split ring R fitted in agroove iu the sleeve 23 above mentioned. 18o

Many changes may be made in the particular construction and generalorganization of several of the elements of my improved device, Withoutdeparting from the spirit of the invention as defined by the claims.

I claim 1. The combination with a head, slides movable radially thereon,and chasers carried by said slides, of a series of levers each having anouter inclined face and pivoted on the head for controlling the outwardmovement of said slides, and a device engaging all of said inclinedfaces for variably positionine' said levers to adapt the chasers forWork of different diameters.

Q. The combinationvvith a head, slides movable radially thereon, andchasers carried by saidslides, of a series of levers pivotally mountedon said head and engaging said slides to control the outward movementthereof, and a beveled ring movable relatively to and engaging' saidlevers for varyina` the normal position thereof to adapt the chasers forWork of different diameters.

3. The combination vvith a head, chasers radially movable thereon, and atapered member carried by each Chaser, of a series of devicesengaging.,r said tapered members for controlling the outward movement ofthe chasers at a certain ratio relative to the advance movement of theWork through the chasers during the cutting operation, a memberpivotally connected with and for moving said devices in unison with andby the advance movement of the Work, and means for variably positioningsaid devices radially of the head for adjusting the normal openingbetween the chasers for differentsizes of work.

l. The. combination with a head, chasers radially movable thereon, and atapered member carried by each Chaser, of a series of levers engagingsaid tapered members extraneously thereof for controlling the outwardmovement of the chasers at a certain ratio relative to the advancemovement of the work through the chasers during the cutting operation, amember pivotally connected with and for moving` said levers over theworking` faces of said tapered members, and -a member slidablelongitudinally of the head and levers for variably positioning thelatter lto different openings between the chasers, wherebyT the lattermay be positioned for work of different diameters.

5. The combination with a head, a series of slides guided for radialmovement thereon, chasers carried by said slides respcc-- and for movingsaid levers longitudinally of the head and along said inclined faces,and means for positioning said levers radially to vary the position ofsaid slides and the chasers carried thereby, to adapt the latter fordifferent sizes of Work.

6. The combination with a head, slides radially movable thereon, chaserscarried by said slides respectively, and members carried by said slideshaving inclined faces, of a sleeve longitudinally movable relatively tothe head, a series of levers pivoted for radial movement on said sleeveand engaging the inclined faces of said slide members respectively, andmeans controlled by the advance movement of the Work through thechasers, to move said sleeve with. said levers longitudinally of thehead to maintain the outivard movement of said slides in a predeterminedratio relative to the advance movement of the Work and to correspond tothe taper of the thread to be cut.

7. The combination With a head,l slides radially movable thereon,chasers carried by said slides respectively, and members carried by saidslides having inclinedA faces, of a sleeve longitudinally movablerelatively to the head, a series of levers pivoted for radial movementon said sleeve and engaging' the inclined faces of said slide-membersrespectively, means controlled by the advance movement of the workthrough the chasers, to move said sleeve with said levers longitudinallyof the head to maintain the outward movement of said slides in apredetermined ratio relative to the advance movement of the ivork and tocorrespond to the taper of the thread to be cut, and means for varyinglthe time of the commencement of sliding movement of said sleeve.

S. The combination with a head, slides radially movable thereon, chaserscarried by said slides respectively, and members carried by said slideshaving inclined faces, of a sleeve longitudinally movable relatively tothe head, a series of levers pivoted for radial movement on said sleeveand engaging the inclined faces of said slide-members respectively,means controlled by the advance movement of the Work through thechasers, to move said sleeve with said levers longitudinally of the headto maintain the outward movement of .said slides in a predeterminedratio relative to the advance movement of the Work and to correspond tothe taper of the thread to be cut,'and a collar a-djnstably mounted insaid sleeve and adapted to be moved longitudinally by the advancemovement of the work, whereby the time of starting` said sleeve movementmay be varied.

9. The eou'lbination with a head, slides radially movable thereon,chasers carried by said slides respectively. and members projecting fromsaid slides and having inclined chasers and movable longitudinally oftheI faces,- of a sleeve mounted for longitudinal movement relative tothe head, a series of levers pivoted on said sleeve for radial movementand engaging the inclinedl faces of said slide-members respectively, areamer centrally disposed relatively to the head and the axis of thehead, and means for transferring the inwardmovement of said reamer ontothe sleeve, to move the latter with the levers longitudinally over saidinclined faces.

10. The combination with a head, chasers radially movable thereon, and atapered member carried by each chaser, of a series of levers engagingsaid tapered members for controlling the outward movement of the chasersto a certain ratio relative to the advance movement of the work throughthe chasers during the cutting operation, a member pivotally connectedwith and for moving all of said devices over said tapered members inunison with and by such advance movement of the work, and resilientmeans tending to open said chasers.

11. The combination with a head, a series of chasers carried thereby andmounted for radial movement thereon, and a member for each chaser andhaving an inclined working face and an abrupt drop-olf face, of leversadapted to travel over said working faces during the cutting operation,means for moving said levers longitudinally in` unison with the work,and means for variably controlling the initial point of engagement o1said levers with said working faces longitudinally thereof.

12. The combination with a head, a series of chasers carried thereby andmounted for radial movement thereon, and a member for each chaser andhaving an inclined working .I

face and an abrupt drop-off face, of levers adapted Ito travel over saidworking faces during the cutting operation, means for moving said leverslongitudinally in unison With the work, and means for limiting theforward movementof said levers.

13. The combination with a head, a series of chasers carried thereby andmounted for radial movement thereon, and amember for each chaser andhaving an inclined working face and an abrupt drop-oli' face, of leversadapted to travel over said working faces during the cutting operation,means for moving said levers longitudinally in unison with the work,said means comprising a sleeve, and means carried by said sleeve tolimit the forward movement thereof.

14. The combination with a head, a series of chasers carried thereby andmounted for radial movement thereon, and a member' for each chaser andhaving an inclined working face and an abrupt drop-off face, of leversadapted to travel over said working faces during the cutting operation,means for moving said levers longitudinally in unison with the Work,said means comprising a sleeve, and an adjusting screw car-- ried bysaid sleeve and adapted to engage the rear face of said head forlimiting the forward movement of said sleeve.

In testimony whereof l affix my signature in presence of two witnesses.

WILLIAM MURGHEY. Witnesses:

H. D. MACDONALD, CHAs. F. SCHMELZ.

